Safety switch mechanism



H. F. KRANTZ.

SAFETY SWITCH MECHANISM.

APPLICATION FILED JUNE 6.1918.

1,342,219. Patented June 1,1920.

INVENTOR om'reo STATES PATENT or-rlce.

HUBERT F. KRANTZ, OE BROOKLYN, NEW YORK, ASSIGNOR TO KRANTZ MANUFAC-TUBING COMPANY,.INC., OF BROOKLYN, NEW YORK, A CORPORATION OF NEW YORK.

SAFETY SWITCH MECHANISM.

To all whom it may concern:

Be it known that I, HUBERT F. KRANTZ residing at Brooklyn, in the countyof Kings and State of New York, have invented certain new and usefulImprovements in a Safety Switch Mechanism, of which the following is aspecification.

This invention relates to a safety switch mechanism, andthe object ofthe invention is to provide an arrangement particularly adapted for theproper and safe control of motor and like circuits.

A more particular object is to provide means adapted to prevent thebreaking of a motor circuit by other than the switch installed for thatpurpose.

A further object is to pI'0V1d, 1n combination with a motor starting, orcircuit controlling, switch and a line-disconnecting switch, safetymeans to prevent off movement of the line-disconnecting swltch at anytime while the circuit controlling switch is on.

A further object is to provide, in the above combination, a guard memberfor the live parts of the line-disconnecting switch mechanism and toarrange the safety means just referred to in such manner that it willserve to prevent movement of said guard member out of guarding positionwhile the circuit controlling switch is. on.

A further object is to provide the guard member with connections such asto cause the line-disconnecting switch to move off when the guard memberis being displaced, and to arrange the safety means in such manner thatsaid connections are not operable to move the line-disconnecting switchoff while the circuit controlling switch is on.

A further object is to provide the guard vmember with retaining meansand to arrange the safety means in a manner to prevent said retainingmeans from being released while the circuit controlling switch is on.

Other objects and aims of the invention more or less specific than thosereferred to above, will be in part obvious and in part pointed out inthe course of the following description of the elements, combinations,arrangements of parts and applications of I Specification of LettersPatent.

Patented J une 1, 1920.

Application filed .Tune 6, 1918. Serial No. 238,501.

principles, constituting the invention, and the scope of protectioncontemplated will -be indicated in the appended claims.

In the accompanying drawings which are to be taken as a part of thisspecification, and in which I have shown merely a preierred form ofembodiment of the invenion:

Figure 1 is a diagrammatic view illustrating a system, or arrangement ofelemeits in conformity with this-invention, an

Fig. 2 is a longitudinal sectional View, partly in elevation, of theline-disconnecting switch mechanism suggested as present in Fig. 1.

Motor circuits, as now commonly installed, include two distinct switchdevices for controlling the supply of current from the mains to themotor: first, a circuit controlling switch, and second, aline-disconnecting switch. The former is of such a type as 'to becapable of successfully and safely breaking the circuit even under veryheavy overload, while the latter is not of this capacity but is onlyintended for mebreaking the running circuit.

The present device is primarily a means to positively prohibit use ofthe line-disconnecting switch as a circuit breaker.

Referring to the drawings for describing the elements suggested therein,the reference character L indicates the line-disconnecting switch, whilethe reference character G indicates the circuit controlling, or motorstarting, switch. The reference character H indicates themotor.

The circuit represented includes wires 1 and 2, which may be consideredas the mains. These enter the housing 3 of the line-disconnecting switchat one end thereof. From the opposite end of the housing 3 wires 4 and 5continue to, and enter the housing 6 of the circuit controlling switch.From the opposite side of the housing dot the circuit controlling switchwires 7 and 8 lead to the motor H. The switch mechanisms L and G arepreferably contained within housings as illustrated, and there may beother features associated with them, such for instance the fuses 9 and10.

The operating handle, as 11, of the linedisconnecting switch is operableto swing the double ended switch blades 12 for connecting the terminals13- 14 and 15-16 together.

The operating handle, as 17, of the circuit controlling switch isadapted to swing the switch blades 18 for controlling circuit betweenthe contacts 19-20 and 21-22.

At 23 is indicated a solenoid coil having a movable core 24 and beingconnected by wires 25 and 26 with the wires 7 and 8 respectively. By theconnection of this coil in shunt in the circuit at a point between thecircuit controlling switch G and the motor, it is apparent that whenevercurrent is flowing in the circuit the coil is energized.

\Vhenever the coil is energized the head 27 at one end of the core 2 1is thrust outwardly and is maintained in its outer position, as shown bythe dotted lines in Fig. 1, as long as the coil remains energized.

When the head 27 is in its outer position it is intended to stand in aposition to obstruct off movement of the switch L.

The construction of the switch L, as shown in Fig. 2, is illustrated forexample as being similar to that disclosed in m pending applicationSerial No. 175,191, and includes a plunger-like part 28 which isconnected with a blade operating toggle 29 in such manner that when thetoggle is made, and the switch blades 12are moved on, as by swinging ofthe handle 11, the part 28 is in a projected position as shown by thedotted lines in Figs. 1 and 2, and must necessarily be withdrawn fromthis position to the position shown in full lines whenever the toggle isbroken. Thus while the switch blades 12 are on the part 28 is projected,while whenever the switch blades are off the part 28 is withdrawn.

A projection 29 is formed upon the part 28. This projection provides arearwardly facing shoulder. 30 and the head 27 of the core of the coilis adapted to stand, when the coil is energized, behind this shoulder soas thus to prevent movement of the part 28 from its projected position.

Whenever, therefore, the current is flow-' ing in the wires 7 and 8, andthe coil 23 is thereby energized, it is impossible to withdraw the part28 for breaking the circuit by the switch L. The operators efforts toswing the handle 11 off will be resisted by engagement of the surface 30against the head 27 and before he can succeed in swinging the handle 11he must necessarily first points in said circuit break the circuit atthe switch G so as to make dead the wires 7 and 8 and denergize the coil23.

As above suggested, in association with the parts thus far described,this invention includes the provision of a guard member, for preventingaccess to live parts'of the line-disconnecting switch. As illustrated,this guard member includes a door, as 31, pivotally mounted, as at 32,as a part of the housing 3. A part 33 is provided concentric with thepivot 32 adapted to move into position in front of the member 28whenever the door is open.

The part 33 is provided with asurface portion 34 which stands to engagethe upper surface of the head 27 when said head is in its outerposition. The head 27 thereby serves to prevent any opening movement ofthe door while the coil is energized. A latch 35is provided at the freeedge of the door operable to move into and out of looking positionbeneath a stationary portion 36 of the housing. A link 37 extends intoproximity with the part 28 so as to prevent unlocking of the latchwhenever the part 28 is in the projected position as suggested in mypending application Serial No. 158,957.

It will be noted that, since the part 28 must be in its projectedposition whenever the head 27 is projected, then the head 27, acting topositively prevent return movement of the part 28 also serves at thesame time to positively prevent unlocking movement of the latch 35. Thedoor, or guard member, 31 may thus not even be unlocked while current isflowing to the motor.

As many changes could be made in this construction without departingfrom the scope of the invention as defined in the following claims, itis intended that all matter contained in the above description or shownin the accompanying drawings, shall be interpreted as illustrative onlyand not in a limiting sense.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. In an electric circuit, the combination with two inclosed switchesconnected at different points in said circuit, of means adapted toprevent the opening of the inclosing casing of one of said switchesprior to an off movement ofthe other switch.

2. In an electric circuit, the combination with two switches connectedat different and inclosing casings for the switches, of electricallyoperable means connected in shunt relation to the said circuit andadapted to prevent the opening of one ca'sing prior to an off movementof the other switch.

3. In a motor circuit, the combination with a circuit-controlling switchand a line-- disconnecting switch having an inclosing thereof prior toan ofi movement of the circuit-controlling switch.

4. In a motor circuit, the combination with a line-disconnecting switchhaving an.

inclosing casing and a circuit-controlling switch, each movable into onand oil positions, of obstructing means adapted to prevent operation ofthe line-disconnecting switch into one of its positions and opening ofthe casing, and means whereby the slicetiveness of said obstructingmeans is dependent upon the position of the circuitcontrolling switch.

5. In a motor circuit, the combination with a line-disconnecting switchhaving an inclosing casing, and a circuit-controlling switch, the latterbeing installed between the line-disconnecting switch and the motor, ofelectrically operable means connected in shunt relation to the circuitbetween the circuit-controlling switch and the motor to prevent ofi'movement of the line-disconnecting switch and opening of the inclosingcasing thereof except when the circuit-controlling switch is off.

6. In an electric circuit, the combination with two switches connectedat different points in said circuits, and removable guard means forguarding certain parts of one of said switches, of means adapted toprevent J removal of said guard means except when the second switch isoff. I

7. In an electric circuit, the combination with two switches connectedat different points in said circuit, removable guard means for guardingcertain parts of one of said switches, and connections whereby to causeofi movement of said mentioned switch whenever said guard means isremoved, of means adapted to prevent operation of said connections andto retain the guard member in guarding position except when the secondswitch is off. In testimony whereof I a'lfix my signature in thepresence of two witnesses.

HUBERT F. KRANTZ. Witnesses:

L. Gnssronn HANDY, MAY SOHULZ.

